OWL2VOWL_work

Fix reference property instance count export addReferenceProperty() …

was reading getIndividualAssertions() from the
HasReference copy (always empty) instead of the main property that
holds assertions collected during processObjectPropertyAssertions().

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

feat: expose object property assertions as instances on relation …

edges

- AbstractProperty: store individual assertion pairs (subject/object IRI)
- AbstractConverter: parse OWLObjectPropertyAssertionAxiom and attach each (subject, object) pair to the corresponding VowlObjectProperty
- JsonGeneratorVisitorImpl: export instances count and individuals list [{subject, object}] in property JSON, mirroring the class node schema

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

init